Investigation of Wilson disease and obstructive liver disease using a random urine specimen
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
CURC | Copper/Creat Ratio, U | No | Yes |
CRETR | Creatinine, Random, U | No | Yes |
CURC: Triple-Quadrupole Inductively-Coupled Plasma Mass Spectrometry (ICP-MS/MS)
CRETR: Enzymatic Colorimetric Assay
Copper (Cu)
Cu (Copper)
Wilson Disease
Wilson's Disease
Urine
Patient Preparation: High concentrations of barium are known to interfere with most metal tests. If barium-containing contrast media has been administered, the specimen should not be collected for at least 96 hours.
Supplies: Urine Tubes, 10 mL (T068)
Collection Container/Tube: Clean, plastic urine collection container with no metal cap or glued insert
Submission Container/Tube: Plastic, 10-mL urine tube or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 3 mL
Collection Instructions:
1. Collect a random urine specimen.
2. See Metals Analysis Specimen Collection and Transport for complete instructions.
2 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 28 days | |
Frozen | 28 days | ||
Ambient | 14 days |
Investigation of Wilson disease and obstructive liver disease using a random urine specimen
The biliary system is the major pathway of copper excretion. Biliary excretion of copper requires an adenosine triphosphate (ATP)-dependent transporter protein. Variants in the gene for the transporter protein cause hepatolenticular degeneration (Wilson disease). Ceruloplasmin, the primary copper-carrying protein in the blood, is also reduced in Wilson disease. Urine copper excretion is increased in Wilson disease due to a decreased serum binding of copper to ceruloplasmin or due to allelic variances in cellular metal ion transporters.
Hypercupriuria (increased urinary copper) is also found in hemochromatosis, biliary cirrhosis, thyrotoxicosis, various infections, and a variety of other acute, chronic, and malignant diseases (including leukemia). Urine copper concentrations are also elevated during pregnancy and in patients taking contraceptives or estrogens.
Low urine copper levels are seen in malnutrition, hypoproteinemia, malabsorption, and nephrotic syndrome. Increased zinc consumption interferes with normal copper absorption from the gastrointestinal tract causing hypocupremia.
COPPER/CREATITINE:
Males:
0-17 years: Not established
> or =18 years: 9-43 mcg/g creatinine
Females:
0-17 years: Not established
> or =18 years: 7-72 mcg/g creatinine
CREATITINE:
> or =18 years old: 16-326 mg/dL
Reference values have not been established for patients who are younger than 18 years.
Humans normally excrete less than 60 mcg/24 hour in the urine.
Urinary copper excretion greater than 60 mcg/24 hour may be seen in:
-Wilson disease
-Obstructive biliary disease (eg, primary biliary cirrhosis, primary sclerosing cholangitis)
-Nephrotic syndrome (due to leakage through the kidney)
-Chelation therapy
-Estrogen therapy
-Mega dosing of zinc-containing vitamins
Because ceruloplasmin is an acute phase reactant, urine copper is elevated during acute inflammation. During the recovery phase, urine copper is usually below normal, reflecting the expected physiologic response to replace the copper that was depleted during inflammation.
No significant cautionary statements
1. Zorbas YG, Kakuris KK, Deogenov VA, Yerullis KB. Copper homeostasis during hypokinesia in healthy subjects with higher and lower copper consumption. Tr Elem Electro. 2008;25:169-178
2. Lech T, Sadlik JK. Contribution to the data on copper concentration in blood and urine in patients with Wilson's disease and in normal subjects. Biol Trace Elem Res. 2007;118(1):16-20
3. Czlonkowska A, Litwin T, Dusek P, et al. Wilson disease. Nat Rev Dis Primers. 2018;4(1):21. doi:10.1038/s41572-018-0018-3
4. Rifai N, Horwath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018
The metal of interest is analyzed by triple-quadrupole inductively-coupled plasma mass spectrometry.(Unpublished Mayo method)
Monday, Thursday
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
82525
82570
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
CURCU | Copper/Creat Ratio, Random, U | 13829-7 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
CRETR | Creatinine, Random, U | 2161-8 |
615258 | Copper/Creat Ratio, U | 13829-7 |